After much procrastination, hemming, and hawing, I finally have a functional online storefront.
I previously had an account with Google Checkout for payment processing, but had exactly one payment processed via that service before it went kaput. I had considered Etsy, Amazon.com, and other possibilities in the past, but for various reasons nothing seemed to meet all my needs.
I had looked into Shopify before, but they did not have the ability to process payments. You had to signup for a Shopify account to create an online store, then signup with another party for payment processing, then integrate the two systems. Probably isn't all that hard, in practice, but it was a barrier to entry, nonetheless. Now I can manage my storefront and payments in the same service, which is convenient.
I've had very little time to set things up, so apologies for the site's appearance. The default theme is pretty nice, but I've been tweaking it per my aesthetic preferences. One thing in particular I want to implement is the ability to have a custom order. Right now, I can easily create a custom product, but if I do so then it's on display for everyone to see (and possibly buy). Perhaps a "hidden" product page would work. I'm sure there's some easy way to create a one-off SKU (shopkeeping unit).
Next steps include setting up a newsletter and some promotional offers for those of you who actually pay attention.
Contact: open.source.soap at gmail